An intervention study with 3000 COPD-patients cluster-randomized after a bloc-randomization of their GP-practice. 18 GP-practices in Ringkøbing-Skjern-Municipality are randomized to receive an active implementation or to an "as usual" group. A neighboring municipality acts as "sleeping" control. With data from registers and a questionnaire-survey the effect on COPD-patients self reported-health, evaluation of health system and changes in distribution of health resources is analyzed. How health professionals perceive the implementation and how it influences their conception, interactions and culture is illustrated by interviews with stakeholders.